Musnad Ahmad 27:1122

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from 'Alqamah ibn Marthad, I heard Salim ibn Razin narrating from Salim ibn 'Abdullah—meaning ibn 'Umar—from Sa'id ibn al-Musayyib, from Ibn 'Umar, from the Prophet (peace be upon him) regarding a man who has a wife, then divorces her, then another man marries her and divorces her before he has consummated the marriage with her; does she return to her first husband? The Messenger of Allah (peace be upon him) said: "Not until she tastes the 'usaylah (the sweetness/intimacy)."